使用大於和小於比較的搜索 CASE 語句

Question

我有一個很大的計算，它將給出數值並且需要比較大於和小於

CASE big_expression 
  WHEN > 0 AND <5 THEN 'Less Than 5 Days'
  WHEN > 5 AND <20 THEN 'Between 5 and 20 Days'
  -

可以這樣做嗎，或者我每次進行比較時都需要使用這些表達式

Answer 1

您可以將 CTE 用於相同的

        WITH data
         AS (SELECT 1 + 2 + 5 + 9 AS big_exp
             FROM   dual)
    SELECT CASE
             WHEN big_exp > 0
                  AND big_exp < 5 THEN 'Less Than 5 Days'
             WHEN big_exp > 5
                  AND big_exp < 20 THEN 'Between 5 and 20 Days'
             ELSE 'Greater than 20 days'
           END
    FROM   data